1. FIELD OF THE INVENTION
The present invention relates generally to electronic systems. More particularly, the invention relates to requests for access to a resource.
2. DESCRIPTION OF THE BACKGROUND ART
Dynamic random access memory (DRAM) is an important form of memory. DRAM can store data with high density because a DRAM cell requires as few as one transistor.
DRAM is commonly organized into memory banks. A single memory bank generally outputs the number of bits needed to fill the width of a data bus. For example, if the data bus is 32 bits wide, then a single memory bank outputs 32 bits. If the data bus is 64 bits wide, then a single memory bank outputs 64 bits. A multiple bank memory system utilizes a plurality of memory banks. By using a plurality of memory banks, memory accesses to different banks may be interleaved to increase performance by more fully utilizing the available data bus bandwidth.
In some memory systems, for example in synchronous DRAM (SDRAM) systems, a plurality of DRAM integrated circuits (often called xe2x80x9cchipsxe2x80x9d) may be used to create a memory bank. In other memory systems, for example in RDRAM developed by Rambus, Inc. of Los Altos, Calif., a single DRAM chip may include multiple memory banks. In other systems, parts with multiple internal banks may be stacked to provide a wider word width.
Despite current advances in memories, as CPU and memory bus speeds continue to increase, further improvements in memory systems are needed.